Trigger mechanism



July 15, 1941. .1. B. SMITH 2,249,232

TRIGGER MECHANISM Filed Feb. 8, 1939 2 Sheets-Sheet 2 INVENTOR JOHN B M/TH H/5 ATTORNEY Patented July 15, 1941 UNITED STATES TENT ()FFICE TRIGGER MECHANISM John B. Smith, Oakland, Calif.

Application February 8, 1939, Serial No. 255,302

13 Claims.

My invention relates to means for releasing a cocked element of a gun; and the broad object of the invention is to provide an improved scar and trigger controlled release mechanism.

Anotherobject is to provide a toggle associated with a scar for holding the element in cocked position.

A further object is to provide a trigger controlled release mechanism for collapsing the toggle to release the cocked element.

Still another object is to provide adjustment means for regulating the trigger poundagc and for adjusting the trigger pull and backlash movements.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of my invention. It is to be understood that I do not limit myself to this disclosure of species of my invention, as I may adopt variant embodiments thereof within the scope of the claims.

Referring to the drawings:

Figure 1 is a side elevational view of my trigger mechanism and housing with the cover plate of the housing removed to show the internal structure.

[Figure 2 is a side view of a modified mechanism, apart from the housing; and

Figure 3 is a similar view showing another modification.

Figure 4 is aview similar to Figure 1, showing another mechanism adapted for a different type of gun; and- Figure 5 shows a modified mechanism, apart from the housing.

Figure 6 shows another modification adapted to a hammer gun.

For the expert rifieman in competition shoot-. ing and for others interested in marksmanship, the trigger mechanisms of stock rifles do not offer the precision in action and adjustment that! is desired. My improved mechanisms are particularly designed as replacement units for standard rifles, and embody mechanical elements which give the delicacy of trigger movement and closeness of adjustment which is required in accurate shooting.

In terms of broad inclusion the trigger mechanism embodying my invention comprises a. toggle for holding an element in cocked position, and trigger controlled means for collapsing the toggle to release the element. In one form of my mechanism the toggle issupported against collapse by a trigger actuated member, and the toggle is allowed to collapse upon retraction of the supporting member. In another form of my mechanism the toggle is locked past dead center and is moved back over center by trigger actuated means to collapse the toggle. In the various embodiments of my mechanism adjustments are provided for regulating the trigger poundage and for adjusting the trigger pull and backlash movements.

In greater detail, the mechanism shown in Figure l of the drawings is particularly designed for use in conjunction with the Winchester model 52 rifle, it being understood however that the mechanism may be adapted for other types of guns. In the preferred form, themechanism is enclosed in a housing 2 preferably made from a block of steel milled to provide suitable recesses for receiving the working parts, and covered by a side plate (not shown) secured by screws threaded into tapped holes 3 provided in the body of the housing. Thehousing is shaped to position its lower face flush with the underside of th stock inside the trigger guard, with the upper portions of the housing projecting into the usual receiver slot below the firing pm.

In the Winchester model 52 rifle, such a hous-g ing is preferably fastened by a pin projecting through hole 4, and a mounting screw threaded up through tapped hole 6 to bear against the receiver forward of the pin in hole 4. When the mounting screw is tightenedup a shoulder l on my housing abuts the rear edge of the receiver slot, thus locking the unit in position. Such a releasable locking arrangement is described in greater detail in my copending application, Serial No. 137,783, filed April 19, 1937.

The working parts of my improved mechanism comprise a toggle sear having a pair of arms 8 and 9 pivotally connected by an elbow pin l0. Arm 8 of the sear has a fixed pivot provided by a pin H pressed into the arm and journaled in counter-bored holes in the housing. The other toggle arm 9 has a floating pivot provided by a pin l2 fixed in the housing and engaging a guide slot l3 extending horizontally into the end of the arm. Arm 9 also has an upwardly projecting lug l4 providing a square sear point l6 for engaging the sear catch ll of firing pin plunger l8 to hold the latter element cocked.

The toggle sear is arranged with its elbow pivot I 0 lying between the. sear point l6 and fixed pivot II, so that the major portion of the firing pin thrust is directed along the arms and against pivot pin II when the toggle is extended; and

the parts are so disposed that the dead center axis passing through sear point l6 and the axis of fixed pivot ll, indicated by the dot and dash line I9, slopes downwardly and forwardly from the sear point. In the cocked position shown in Figure l, the axis of elbow pin l lies slightly below the dead center axis, thus causing a component of the firing pin thrust to be directed downwardly against the toggle and tending to collapse the toggle downwardly from the cocked position.

Collapsing movement is permitted by the floating pivot |2--|3 which acts to stabilize the toggle yet permits a limited degree of rotation about the elbow pin. I have found that a straight guide slot |3 disposed below the sear point l6 and lying substantially horizontally in the cocked position serves to properly guide the toggle in its collapsing movement. The location of pin I2 is important in determining the rate at which sear point l6 drops away from sear lug II. By positioning the pin higher up and further back a faster drop is attained. Having slot |3 open out at the end of arm 9 is also important in facilitating manufacture and assembly.

The toggle sear is urged upwardly into cocked position by a sear spring 2| compressed between adjusting screw 22 and toggle arm 8. Screw 22 is threaded in a hole opening out on the lower face of the housing, so that the pressure on the toggle may be conveniently adjusted. An adjustable stop screw 23 is also provided in the upper portion of the housing for engaging arm 8 to limit upward movement of the toggle. This screw is adjusted so that the axis of the elbow pivot lies below dead center in the cocked position.

Trigger controlled means are provided for supporting the toggle sear against collapse to hold element It cocked. For this purpose a supporting member or pawl 24 is pivotally mounted below the toggle on a pin 26, and is provided at its upper end with a sear point 21 engageable under a sear point 28 on toggle arm 8. These sear points are preferably disposed adjacently below the elbow axis, and pawl pin 26 is preferably disposed vertically below the sear points, so that the downward collapsing thrust on the toggle is directed against the pawl pivot, thus providing a stable mechanism in the cocked position. Of course the component of firing pin thrust carried by the pawl is not large because the axis of elbow pin i0 is close to dead center in cocked position and the toggle bears only lightly on the pawl.

When pawl 24 is rotated back out of supporting engagement with the toggle the latter drops down to release the cocked element I8. It is to be noted that sear points 21 and 28 separate by a sliding action transverse of the thrust component directed downwardly against the toggle, whereby the release movement of pawl 24 is substantially independent of the firing pin thrust, even though a small component of the thrust is carried by the pawl. An important feature of my improved mechanism is that the engaging surfaces of sear points 21 and 28 are curved on a radius from the axis of pawl pin 26 so that the pawl may slide out of engagement without lifting or lowering the elbow pin the slightest amount. This arrangement therefore holds sear point I6 in predetermined position until the instant the toggle drops, which insures positive cocking and smooth trigger pull.

Pawl member 24 is retracted to release the toggle sear by a trigger 29 pivoted on the housing by a pin 3| and having oppositely extending arms 32 and 33, the forward arm 3-2 of which overlappingly engages a rearwardly projecting arm 34 of the pawl. The engaging portions of arms 32 and 34 he substantially midway between pivot pins 3| and 26 and in a plane passing through the axes of these pivots for maximum leverage and minimum sliding movement between the engaging surfaces. This feature also promotes smooth trigger action.

Pawl 24 is urged into engagement with the toggle sear and the trigger is held in forward position by a spring 36 bearing upwardly against pawl arm 34. A plug screw 31 is threaded into the housing behind this spring for adjusting the spring pressure on the arm, and this screw is conveniently accessible from the lower side of the housing. Since the trigger is pulled against this spring the compression of the latter determines the poundage pull of the trigger. This is an important adjustment in a trigger mechanism, and since my release pawl 24 slides out from under the toggle sear with minimum and unvarying resistance, the trigger pull is jsubstantially independent of the firing pin thrust and therefore the poundage pull may be adjusted within close limits and there is practically no tendency of the parts to get out of adjustment.

In order to limit the draw and backlash movements of the trigger, a pair of adjusting screws 38 and 39 are threaded into the housing from the lower face to provide stops for the pawl and trigger; screw 38 being engageable with trigger arm 33 and screw 39 with pawl arm 34. By backing off screw 38 the amount of overlapping engagement between sear points 21 and 28 is increased, thereby increasing the length of trigger pull before the firing pin is released; and by setting up this screw 'the pull is shortened. I

have succeeded in getting small release movements without difficulty, such as pulls of .001 to .0015 inch at the center of the finger engaging curve of the trigger.

By adjusting the setting of stop screw 39 the amount of backlash movement after separation of sear points 21 and 28 may be regulated. Backlash is undesirable in trigger pulls, and may be substantially entirely eliminated in my mechanism by proper setting of screw 39.

A modified form of mechanism is shown in Figure 2, in which the axis of elbow pin I0 is disposed above dead center, and the operation depends upon shifting the elbow axis back across dead center for collapsing the toggle. In this construction toggle arm 8 is provided with a lip 4| underlying arm 32 of the trigger, so that when the trigger is pulled the axis of elbow pivot I0 is pulled down. As soon as the elbow axis crosses dead center the thrust of the firing pin causes the toggle to collapse downwardly to release the firing pin. Spring 2| under the toggle operates to re-set the linkage, and upward movement of the elbow pin is limited in the cooked position by adjusting screw 38 of the trigger.

In this mechanism poundage spring 36 and adjusting screw 39 engage trigger arm 32; and stop screw 39 serves to control the backlash movement as before. This screw is preferably set so that movement of the trigger is stopped as soon as the elbow axis of the toggle crosses dead center. The toggle is not so limited however and may Collapse further since lip 4| is free-to move down from trigger arm 32. Since spring 2| acts to elevate trigger arm 32 as well as the toggle,

spring 36 may be eliminated. In that event spring 2| performs the double function of resetting the toggle and providing the poundage pull for the trigger.

Figure 3 shows another modification comprising a separate sear arm 42 pivoted on a pin 4% and supported in cocked position by an upstanding toggle having arms 45 and t6, the lower arm having a fixed pivot 41 and the upper arm being connected to the sear by a pin 48. The toggle is arranged with the axis of its elbow pin 59 past the dead center axis 5| and is'collapsible in the opposite directionby shifting the elbow axis back over center.

The toggle is collapsed by a trigger 52 having an arm 53 engaging over a. lip 54 of the lower to'Jgle arm. Adjustable stop screws 56 and 5! are engageable with oppositely extending arms 53 and 58 ofthe trigger for limiting movement of the parts, it being seen that stop 5'l'holds the toggle against outward collapse in the cocked position. A spring 59 engaging the toggle serves to urge the toggle and connected sear into cocked position, and also serves to hold the trigger forward. A screw 6| under the spring serves to adjust the poundage pull.

Figure 4 shows another modification of my trigger mechanism, particularly adapted for a Remington model 37 rifle. The housing 62 of this mechanism is mounted within the rifle by a pair of pins passing'through holes 53 and M in the housing. In this type of gun the sear shoulder B6 of the firing pin plunger 61 is located considerably forward of the trigger in the cocked position, and in order to accommodate my mechanism to this spacing a sear arm 68 is pivoted on a pin 69 located back of shoulder 55. A sear point I! on arm 68 engages shoulder 55 to hold element 61 in cocked position, and in this rela= tionship sear arm 69 is under tension.

Sear 68 is held up by a toggle having a lower arm 12 with a fixed pivot I3 and an upper arm Hi pivoted to the sear by a pin 76. The axis of elbow pin 11 is back of the dead center axis 18 so that the downward thrust of the sear tends to collapse the toggle rearwardly. The elbow pin of the toggle is limited in its forward movement by an adjustable stop screw 19 engageable with the sear, and the toggle is urged into cocked position by a spring 8| interposed between toggle arm 12 and the sear.

The toggle is held against collapse by a pawl member 82 pivoted on a pin 83 and providing a sear point engageable under a sear point provided by lip 84 on toggle arm 12. Pawl 82 is retractable to disengage the sear points by a trigger 86 pivoted on pin 81 and having oppositely extending arm's 88 and 89, one of which overlappingly engages an arm 9| of the release pawl.

.An adjustable stop screw 92 and spring 93 are engageable under pawl arm 9| to re-set the parts and limit backlash movement; and an adjustable stop screw 94 is engageable under trigger arm 89 to limit engaging movement of the sear points on pawl 82 and lip 84.

Figure 5 shows a variant form of mechanism, comprising toggle arms 96 and 91 arranged to be shifted back over dead center to collapse the toggle. The toggle is shifted by a trigger arm 99 engageable with a lip 99 on toggle arm 96. In this case spring 93 and stop screw 92 engage directly under trigger arm 98. Another adjusting screw IM serves to limit outward collapsing of the toggle in the cooked position. A different type of toggle is also illustrated, wherein one of the toggle arms 91 is a compression pin having rounded ends seated in conical sockets formed in the end of toggle arm 96 and sear 68.

Figure 6 shows a modified mechanism adapted for hammer guns. Toggle arms I02 and 13 are mounted on a hired pivot I04 and are pinned together and to spring pressed hammer E06 by pivots It? and I08. The axis of elbow pivot Nil is above the dead center axis in the cocked po sition, and the toggle is pulled down to collapse it by a trigger having an arm we overlying a lip H i formed on a depending portion of toggle arm use. A spring H2 engaging under toggle arm Hi2 serves to re-set both the toggle and trigger; and adjustable stops H3 and lid engageable under the trigger arms limit movement of the parts.

I claim:

1. A trigger mechanism for releasing a cocked element, comprising a sear engageabl with the element, a toggle connected with the sear for holding the element cocked and having its elbow axis ofi dead center in the cooked position, a trigger for shifting the elbow axis over dead center to collapse the toggle, and means for adjusting the elbow axis relative to dead center.

2. A trigger mechanism for releasing a cocked element, comprising a sear engageabl with the element, a toggle connected with the sear for holding the element cooked and having its elbow axis ofi' dead center in the cocked position, a trigger for shifting the elbow axi over dead center to collapse the toggle, means for adjusting the elbow axis relative to dead center, and a spring for urging the toggle toward cocked position.

3. A trigger mechanism for releasing a cooked element, comprising a toggle for holding the element cocked and having its elbow axis off dead center in the cocked position, a trigger having oppositely extending arms one of which is engageable with the toggle for shifting the elbow axis over dead center to collapse the toggle, a stop engageable with said arm for limiting movement of the trigger after the elbow axis has been shifted over dead center, and stop means engageable with the other arm of the trigger for holding the toggle against collapse in the cooked position.

4. A trigger mechanism forreleasing a cooked element, comprising a toggle for holding the element cooked and having its elbow axis off dead center in the cocked position, a trigger having oppositely extending arms one of which is engageable with the toggle for shifting the elbow axis over dead center to collapse the toggle, adjustable stop means engageable with th other arm of the trigger for holding the toggle against collapse in the cocked position, and an adjustable stop engageable with the toggle engaging sear, a spring interposed between the toggle and sear for applying a transverse on the toggle, and

trigger means for controlling the collapsing movement of said toggle.

7. A trigger mechanism for releasing a cocked element, comprising a tension sear for releasably holding the element, a toggle for holding the sear and collapsible to release it, and trigger means for controlling the collapsing movement of said toggle.

8. In a trigger mechanism for releasing a cocked element, a sear for releasably holding the element, a pivoted toggle arm, a second toggle arm comprising a pin seated in sockets in the end of'the first arm and the sear, said toggle being arranged to hold the sear and collapsible to release it, and trigger means for controlling the collapsing movement of said toggle.

9. A trigger mechanism for releasing a cooked element, comprising sear means for releasably holding said element and including a pivotally mounted arm, a retractable release member engageable with said arm, a trigger separate from said member for retracting the release member, a stop engageable with said member for limiting its retracting movement, and a stop engageable with said trigger for limiting the degree of engagement of said member with the arm.

10. A trigger mechanism for releasing a cooked 'element, comprising sear means for releasably holding said element and including a pivotally mounted arm, a retractable release member engageable with said arm, a trigger separate from said membe for retracting the release member, a stop engageable with said member for limiting its retracting movement, a stop engageable with said trigger for limiting the degree of engagement iOf said member with the arm, and a spring bearing against said member for urging it into engagement with the arm.

11. A trigger mechanism for-releasing a cocked element, comprising sear means for releasably holding said element and including a pivotally mounted arm, a retractable release member engageable with said arm, a pivotally mounted trigger separate from said member having oppositely extending portions one of which is engageable with said member for retracting it, a stop engageable with the other trigger portion for limiting the degree of engagement of said member with the arm, and a stop engageable with said member for limiting its retracting movement.

12. A trigger mechanism for releasing a cooked element, comprising sear means for releasably holding said element and including a pivotally mounted arm, a pivotally mounted release member engageable with said arm, and a pivotally mounted trigger engageable with said member for retracting it, the engaging surfaces of said trigger and release member lying substantially in a plane passing through the pivot axes of the trigger and said member when the latter is engaged with said arm.

13. A trigger mechanism for releasing a cocked element, comprising sear means for releasably holding said element and including a plvotally mounted arm, and a pivotally mounted trigger controlled member engageable with said arm and turnable out of engagement therewith, the engaging surface of said member being curved on a radius from the pivot axis of said member.

JOHN B. SMITH. 

